diff options
| -rw-r--r-- | fs/nfsd/nfs4xdr.c | 31 |
1 files changed, 31 insertions, 0 deletions
diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c index d9d7fa94967f..9d76ee311ddc 100644 --- a/fs/nfsd/nfs4xdr.c +++ b/fs/nfsd/nfs4xdr.c @@ -1597,12 +1597,39 @@ nfsd4_opnum_in_range(struct nfsd4_compoundargs *argp, struct nfsd4_op *op) return true; } +/* + * Return a rough estimate of the maximum possible reply size. Note the + * estimate includes rpc headers so is meant to be passed to + * svc_reserve, not svc_reserve_auth. + * + * Also note the current compound encoding permits only one operation to + * use pages beyond the first one, so the maximum possible length is the + * maximum over these values, not the sum. + */ +static int nfsd4_max_reply(u32 opnum) +{ + switch (opnum) { + case OP_READLINK: + case OP_READDIR: + /* + * Both of these ops take a single page for data and put + * the head and tail in another page: + */ + return 2 * PAGE_SIZE; + case OP_READ: + return INT_MAX; + default: + return PAGE_SIZE; + } +} + static __be32 nfsd4_decode_compound(struct nfsd4_compoundargs *argp) { DECODE_HEAD; struct nfsd4_op *op; bool cachethis = false; + int max_reply = PAGE_SIZE; int i; READ_BUF(4); @@ -1652,10 +1679,14 @@ nfsd4_decode_compound(struct nfsd4_compoundargs *argp) * op in the compound wants to be cached: */ cachethis |= nfsd4_cache_this_op(op); + + max_reply = max(max_reply, nfsd4_max_reply(op->opnum)); } /* Sessions make the DRC unnecessary: */ if (argp->minorversion) cachethis = false; + if (max_reply != INT_MAX) + svc_reserve(argp->rqstp, max_reply); argp->rqstp->rq_cachetype = cachethis ? RC_REPLBUFF : RC_NOCACHE; DECODE_TAIL; |